Cyclopropane derivatives

ABSTRACT

Cyclopropane acids and derivatives thereof useful as intermediates, insecticidally active esters of these acids, compositions comprising these esters and methods of using the same. The compounds involved have the formula: ##STR1## wherein R 2  represents an α-branched alkyl group containing from 3 to 6 carbon atoms, and R represents either (a) hydroxy, halo or alkoxy of up to six carbon atoms, or (b) the group --OR 1  where R 1  is the residue of an alcohol of formula R 1  OH which forms an insecticidal ester with chrysanthemic acid, permethrin acid or cyhalothrin acid.

This is a division of application Ser. No. 712,252 filed Mar. 15, 1985,now U.S. Pat. No. 4,661,488.

This invention relates to novel cyclopropane acids and derivativesthereof useful as intermediates, and to insecticidally active esters ofthese acids and compositions comprising them. The invention also relatesto processes for preparing the novel acids and derivating and to novelcompounds useful in such processes.

In a first aspect this invention provides novel cyclopropane compoundsof formula I: ##STR2## wherein R² represents cycloalkyl or an α-branchedalkyl group, preferably containing from 3 to 6 carbon atoms, and either(a) R represents hydroxy, halo (especially chloro) or alkoxy of up to 6carbon atoms, wherein such compounds are useful as intermediates forinsecticides, or (b) R represents the group --OR¹ where R¹ is theresidue of an alcohol of formula R¹ OH which forms an insecticidal esterwhen combined with chrysanthemic acid or permethrin acid or cyhalothrinacid. Permethrin acid is 3-(2,2-dichlorovinyl)-2,2 dimethylcyclopropanecarboxylic acid and cyhalothrin acid is3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylic acid.

More particularly R represents a group of the following general formula:##STR3## wherein X is oxygen, sulphur, vinylene or a group of formula--CR⁵ ═Y-- where Y is nitrogen or CR⁵, R⁴ is hydrogen, methyl, cyano orethynyl, each R⁵ is selected from hydrogen, halogen, and alkyl of up to4 carbon atoms optionally substituted with halogen, and R⁶ is hydrogen,halogen, alkyl of up to 4 carbon atoms, alkenyl of up to 6 carbon atoms,phenyl, phenoxy or benzyl, or phenyl, phenoxy or benzyl substituted withhalogen or alkyl.

It will be appreciated that the compounds of formula I are capable ofexisting in different isomeric forms and as mixtures of isomers. Thusthere are cis and trans isomers arising from the substitution pattern onthe cyclopropane group and optical isomerism arises from the presence ofthe two chiral centres in the cyclopropane group leading to thepossibility of (+)-cis, (-)-cis, (+)-trans and (-)-trans isomers.Further isomerism may be present in the insecticidally active esters ofthe invention if the alcohol moiety contains an alkenyl group or one ormore chiral centres. All such individual isomeric forms and mixturesthereof, including racemates, are within the scope of the invention.

Specific compounds according to formula I useful as intermediateswherein R represents an alkoxy group of up to 6 carbon atoms include themethyl, ethyl, propyl and butyl esters of the acids of formula I whereinR² is one of prop-2-yl, but-2-yl, pent-2-yl, pent-3-yl,2-methylprop-2-yl, 2-methylbut-2-yl, cyclopropyl, and cyclohexyl.

Particularly preferred compounds include:

ethyl (±)-trans-2,2-dimethyl-3-(2-prop-2-ylpyrimidin-5-yl)cyclopropanecarboxylate,

ethyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]-cyclopropanecarboxylate,

and the corresponding methyl and 2-methylprop-2-yl-esters.

The compounds of formula I wherein R is alkoxy of up to 6 carbon atomsmay be prepared from the appropriately substituted 5-bromopyrimidine bythe following reaction sequence:

(a) A 2-α-branched alkyl-5-bromopyrimidine is converted to thecorresponding 5-formyl derivative by formation of a Grignard product,followed by treatment with dimethylformamide, thus: ##STR4##

(b) The 5-formylpyrimidine is reacted with an O,O-dialkylalkoxycarbonylmethylphosphonate in the presence of a base such as sodiumhydride to give a 3-(pyrimidin-5-yl)propenoate, thus: ##STR5##

(c) The pyrimidinylpropenoate is reacted with an isopropyl triphenylphosphonium salt in the presence of an organo metallic reagent such asn-butyllithium to give the cyclopropane ester, thus: ##STR6## wherein R²has the meaning given above and R⁹ is an alkyl of up to 6 carbon atoms.The starting material or intermediates referred to in (a) to (c) may begenerically described as compounds of the formula: ##STR7## wherein Z isbromo, formyl or a group of formula ##STR8## wherein R² and R⁹ have themeanings given above.

In an alternative procedure for preparing the3-pyrimidin-5-yl-propenoates a 5-bromopyrimidine may be reacted directlywith an alkyl propenoate (especially 1,1-dimethylethyl-propenoate) inthe presence of a palladium II salt (e.g. palladium II acetate),tetramethyl ethylene diamine and, preferably, a phosphine derivative(e.g. triphenyl phosphine), thus: ##STR9##

Some of the 5-bromopyrimidines used as starting materials in thissequence are novel. They can be prepared by reaction of a mucobromicacid derivative with an appropriate amidine, followed by decarboxylationof the pyrimidine carboxylic acid thus: ##STR10##

An alternative procedure for preparing the compounds of Formula Iwherein R is alkoxy of up to 6 carbon atoms, and R² is a definedhereinabove employs the following reaction sequence:

(a) The ylid obtained by treating a phosphonium salt of formula:

    [R.sup.7 O--CH.sub.2 --P(R.sup.8).sub.3 ].sup.+ Y.sup.-

wherein Y⁻ is any suitable anion, e.g. the chloride or bromide ion, andR⁷ and R⁸ are alky or aryl groups, preferably R⁷ is alkyl of up to 6carbon atoms such as methyl or ethyl and R⁸ is phenyl, with a strongbase in an aprotic solvent preferably dimsyl sodium in dimethylsulphoxide (obtained by reaction of sodium hydride with dimethylsulphoxide), is reacted with a compound of formula: ##STR11## to obtaina compound of formula III ##STR12##

(b) The compound of formula III is treated with phosphoryl chloride anddimethylformamide under the conditions of the Vilsmeier-Haack reactionto obtain a compound of formula IV and/or a compound of formula V##STR13##

(c) Compound IV and/or compound V is reacted with an amidine of formula:##STR14## preferably in the presence of a base such as sodium methoxidein methanol to provide the compound of formula I wherein R is alkoxy asdefined above.

The compounds of formulae III, IV and V have not previously beendescribed. Accordingly a further aspect the present invention providescompounds of formula III, IV and V are hereinbefore defined useful asintermediates for the production of compounds of formula I.

Preferred compounds of formula III include the (±)-cis and (±)-transisomers of the compounds where R is methoxy or ethoxy and R⁷ is alkyl ofup to 6 carbon atoms including the following:

methyl (±)-trans-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

methyl (±)-cis-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

ethyl (±)-trans-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

ethyl (±)-cis-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

The corresponding compounds of formula IV and formula V are alsopreferred, including the following:

methyl(±)-trans-3-[(E,Z)-1-formyl-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

methyl(±)-cis-3-[(E,Z)-1-formyl-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate

methyl(±)-trans-3-[(E,Z)-2-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate

methyl(±)-cis-3-[(E,Z)-2-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate

together with the corresponding ethyl esters.

Further details of all these processes are set forth hereinafter in theExamples. The compounds of formula I wherein R represents hydroxy may beobtained by hydrolysis of the alkyl esters, preferably by alkalinehydrolysis using eg. aqueous alcoholic sodium hydroxide, and may be useddirectly in the synthesis of insecticidally useful esters or may befirst converted to the compounds of formula I wherein R represents halo,preferably chloro, by reaction with a suitable halogenating agent suchas thionyl chloride. Specific insecticidally useful compounds accordingto the invention include the esters derived from each of:

4-methyl-2,3,5,6-tetrafluorobenzyl alcohol

pentafluorobenzyl alcohol

4-allyl-2,3,5,6-tetrafluorobenzyl alcohol

4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol

3-phenoxybenzyl alcohol

α-cyano-3-phenoxybenzyl alcohol

6-phenoxypyrid-2-ylmethanol

1-cyano-1-(6-phenoxypyrid-2-yl)methanol

3-(4-chlorophenoxybenzyl)alcohol

α-ethynyl-3-phenoxybenzyl alcohols

1-(6-phenoxypyrid-2-yl)ethanol

4-fluoro-3-phenoxybenzyl alcohol

α-cyano-4-fluoro-3-phenoxybenzyl alcohol

5-benzyl-3-furylmethanol

2-allyl-3-methyl-4-hydroxycyclopent-2-enone

2-methyl-3-phenylbenzyl alcohol

including, where appropriate, single isomers and racemates thereof, andeach of the acids of formula I (in the form of the racemic mixture ofthe trans isomers), or a single isomer thereof, wherein R² is one ofprop-2-yl, but-2-yl, pent-2-yl, pent-3-yl, 2-methylprop-2-yl,2-methylbut-2-yl, cyclopropyl and cyclohexyl.

Particularly preferred compounds include:

4-methyl-2,3,5,6-tetrafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound I").

4-allyl-2,3,5,6-tetrafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound II").

3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound III").

(±)-α-cyano-3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound IV").

6-phenoxypyrid-2-ylmethyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound V").

(±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound VI").

2-methyl-3-phenylbenzyl(±)-trans-2,2-dimethyl-3-[2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound VII").

4-fluoro-3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound VIII").

(±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(±)-trans-2,2-dimethyl-3-(2-prop-2-yl-pyrimidin-5-yl)cyclopropanecarboxylate (hereinafter "Compound IX").

(±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(±)-trans-2,2-dimethyl-3-(2-cyclohexylpyrimidin-5-yl)cyclopropanecarboxylate (hereinafter "Compound X").

(±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(+)-trans-2,2-dimethyl-3-(2-cyclopropylpyrimidin-5-yl)cyclopropanecarboxylate (hereinafter "Compound XI").

(±)-1-(6-phenoxypyrid-2-yl)ethyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl)cyclopropanecarboxylate (hereinafter "Compound XII").

pentafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound XIII").

(±)-α-ethynyl-3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound XIV").

4-methoxymethyl-2,3,5,6-tetrafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (hereinafter "Compound XV").

2-methyl-3-phenylbenzyl(±)-trans-2,2-dimethyl-3-(2-prop-2-ylpyrimidin-5-yl)cyclopropanecarboxylate (hereinafter "Compound XVI").

The insecticidally active compounds of the invention according toFormula I are esters and may be prepared by conventional esterificationprocesses, of which the following are examples.

(a) An acid of formula: ##STR15## where Q represents the hydroxy groupand R² has any of the meanings given hereinabove, may be reacteddirectly with an alcohol of formula R¹ --OH (III) where R¹ has any ofthe meanings given hereinabove, the reaction preferably taking place inthe presence of an acid catalyst, for example, dry hydrogen chloride, ora dehydrating agent, such as for example, dicyclohexyl carbodiimide.

(b) An acid halide of formula II where Q represents a halogen atom,preferably a chlorine atom, and R² has any of the meanings givenhereinabove, may be reacted with an alcohol of formula III, the reactionpreferably taking place in the presence of a base, for example,pyridine, alkali metal hydroxide or carbonate, or alkali metal alkoxide.

(c) An acid of formula II where Q represents the hydroxy group or,preferably, an alkali metal salt thereof, may be reacted with halide offormula Q¹ --R¹ (IV) wherein Q¹ represents a halogen atom, preferablythe chlorine atom, and R¹ has any of the meanings given hereinabove, orwith the quaternary ammonium salts derived from such halides withtertiary amines, for example pyridine, or trialkyl amines such astriethylamine.

(d) A lower alkyl ester of formula (II) where Q represents a loweralkoxy group containing up to six carbon atoms, preferably the methoxyor ethoxy group, and R² has any of the meanings given hereinabove, isheated with an alcohol of formula III to effect a transesterificationreaction. Preferably the process is performed in the presence of asuitable catalyst, for example, an alkali metal alkoxide, such as sodiummethoxide, or an alkylated titanium derivative, such as tetramethyltitanate.

All of these conventional processes for the preparation of esters may becarried out using solvents and diluents for the various reactants whereappropriate, and may be accelerated or lead to higher yields of productwhen performed at elevated temperatures or in the presence ofappropriate catalysts, for example phase-transfer catalysts.

The preparation of individual isomers may be carried out in the samemanner but commencing from the corresponding individual isomers ofcompounds of formula II. These may be obtained by conventional isomerseparation techniques from mixtures of isomers. Thus cis and transisomers may be separated by fractional crystallisation of the carboxylicacids or salts thereof, whilst the various optically active species maybe obtained by fractional crystallisation of salts of the acids withoptically active amines, followed by regeneration of the optically pureacid. The optically pure isomeric form of the acid (or its equivalentacid chloride or ester) may then be reacted with the appropriate alcoholto produce a compound of formula I in the form of an individually pureisomer thereof.

The compounds of formula I may be used to combat and controlinfestations of insect pests and also other invertebrate pests, forexample, acarine pests. The insect and acarine pests which may becombatted and controlled by the use of the invention compounds includethose pests associated with agriculture (which term includes the growingof crops for food and fibre products, horticulture and animalhusbandry), forestry, the storage of products of vegetable origin, suchas fruit, grain and timber, and also those pests associated with thetransmission of diseases of man and animals.

In order to apply the compounds to the locus of the pests they areusually formulated into compositions which include in addition to theinsecticidally active ingredient or ingredients of formula I suitableinert diluent or carrier materials, and/or surface active agents. Thecompositions may also comprise another pesticidal material, for exampleanother insecticide or acaricide, or a fungicide, or may also comprisean insecticide synergist, such as for example dodecyl imidazole,safroxan, or piperonyl butoxide.

The compositions may be in the form of dusting powders wherein theactive ingredient is mixed with a solid diluent or carrier, for examplekaolin, bentonite, kieselguhr, or talc, or they may be in the form ofgranules, wherein the active ingredient is absorbed in a porous granularmaterial for example pumice.

Alternatively the compositions may be in the form of liquid preparationsto be used as dips or sprays, which are generally aqueous dispersions oremulsions of the active ingredient in the presence of one or more knownwetting agents, dispersing agents or emulsifying agents (surface activeagents).

Wetting agents, dispersing agents and emulsifying agents may be of thecationic, anionic or non-ionic type. Suitable agents of the cationictype include, for example, quaternary ammonium compounds, for examplecetyltrimethyl ammonium bromide. Suitable agents of the anionic typeinclude, for example, soaps, salts of aliphatic monoesters of sulphuricacid, for example sodium lauryl sulphate, salts of sulphonated aromaticcompounds, for example sodium dodecylbenzenesulphonate, sodium, calciumor ammonium lignosulphonate, or butylnaphthalene sulphonate, and amixture of the sodium salts of diisopropyl- and triisopropylnaphthalenesulphonates. Suitable agents of the non-ionic type include, for example,the condensation products of ethylene oxide with fatty alcohols such asoleyl alcohol or cetyl alcohol, or with alkyl phenols such as octylphenol, nonyl phenol and octyl cresol. Other non-ionic agents are thepartial esters derived from long chain fatty acids and hexitolanhydrides, the condensation products of the said partial esters withethylene oxide, and the lecithins.

The compositions may be prepared by dissolving the active ingredient ina suitable solvent, for example, a ketonic solvent such as diacetonealcohol, or an aromatic solvent such as trimethylbenzene and adding themixture so obtained to water which may contain one or more knownwetting, dispersing or emulsifying agents.

Other suitable organic solvents are dimethyl formamide, ethylenedichloride, isopropyl alcohol, propylene glycol and other glycols,diacetone alcohol, toluene, kerosene, white oil, methylnaphthalene,xylenes, and trichloroethylene, N-methyl-2-pyrrolidone andtetrahydrofurfuryl alcohol (THFA).

The compositions which are to be used in the form of aqueous dispersionsor emulsions are generally supplied in the form of a concentratecontaining a high proportion of the active ingredient or ingredients,the said concentrate to be diluted with water before use. Theseconcentrates are often required to withstand storage for prolongedperiods and after such storage, to be capable of dilution with water toform aqueous preparations which remain homogenous for a sufficient timeto enable them to be applied by conventional spray equipment. Theconcentrates may contain 10-85% by weight of the active ingredient oringredients. When diluted to form aqueous preparations such preparationsmay contain varying amounts of the active ingredient depending upon thepurpose for which they are to be used. For agricultural or horticulturalpurposes, an aqueous preparation containing between 0.0001% and 0.1% byweight of the active ingredient is particularly useful.

In use the compositions are applied to the pests, to the locus of thepests, to the habitat of the pests, or to growing plants liable toinfestation by the pests, by any of the known means of applyingpesticidal compositions, for example, by dusting or spraying.

The compositions of the invention are toxic to a variety of insect andother invertebrate pests, including, for example, the following:

Myzus persicae (aphids)

Aphis fabae (aphids)

Megoura viceae (aphids)

Aedes aegypti (mosquitoes)

Dysdercus fasciatus (capsids)

Musca domestica (houseflies)

Pieris brassicae (white butterfly, larvae)

Plutella maculipennis (diamond back moth, larvae)

Phaedon cochleariae (mustard beetle)

Tetranychus cinnabarinus (carmine spider mite)

Tetranychus urticae (red spider mites)

Aonidiella spp. (scale insects)

Trialeuroides spp. (white flies)

Blattella germanica (cockroaches)

Spodoptera littoralis (cotton leaf worm)

Heliothis virescens (tobacco budworms)

Chortiocetes terminifera (locusts)

Diabrotica spp. (rootworms)

Agrotis spp. (cutworms)

Chilo partellus (maize stem borers)

The compounds of formula I and compositions comprising them have shownthemselves to be particularly useful in controlling acarine pests ofplants such as red mites and rust mites as well as lepidopteran pests ofcotton, for example Spodoptera spp. and Heliothis spp. The compounds mayalso be used to combat pests which inhabit the soil, for exampleDiabrotica spp. They may also be useful in combating insect and acarinepests which infest domestic animals, such as Lucilla sericata, andixodid ticks such as Boophilus spp., Ixodes spp. Amblyomma spp.Rhipicephalus spp., and Dermaceutor spp. They may be effective incombating both susceptible and resistant strains of these pests in theiradult, larval and intermediate stages of growth, and may be applied tothe infested host animal by topical, oral or parenteral administration.

The following Examples illustrate various aspects of this invention. Inthe preparation Examples the products were usually identified andcharacterised by means of nuclear magnetic resonance spectroscopy andinfra red spectroscopy. In each case where a product is specificallynamed its spectral characteristics are consistent with the assignedstructure.

EXAMPLE 1

This Example illustrates the preparation of pivalamidine hydrochloride.

A stirred mixture of trimethylacetonitrile (43 g; 0.51M) and dry ethanol(24 g, 0.51M) was cooled using an ice/salt bath whilst dry hydrogenchloride gas was passed into the mixture over a period of 90 minutes,until a total of 21 gms had been taken up. The mixture was then kept for2 days at the ambient temperature after which it was diluted with drydiethyl ether (500 cm³) to precipitate ethyl trimethyl acetimidatehydrochloride which was collected by filtration (34.5 g). To this wasadded portionwise a solution of dry ammonia gas (6 g) in dry ethanol (50cm³) with vigorous stirring. The solid gradually dissolved during thecourse of the addition and the resultant solution was kept at theambient temperature for 20 hours after which the solvent was removed byevaporation under reduced pressure and the residual solid washed withdiethyl ether to yield pivalamidine hydrochloride (23 g).

EXAMPLE 2

This Example illustrates the preparation of5-bromo-2-(2-methylprop-2-yl)pyrimidine-4-carboxylic acid.

A solution of sodium ethoxide in ethanol (14.5 cm³ of the solutionobtained by dissolving sodium (1.38 g) in dry ethanol (24 cm³)) wasadded carefully to a stirred mixture of pivalamidine hydrochloride (5.18g) and dry ethanol (5 cm³) at 40° C. After stirring the mixture for afurther 10 minutes a solution of mucobromic acid (5.4 cm³ of thesolution obtained by dissolving mucobromic acid (5.16 g) in dry ethanol(8.0 cm³)) was added to the mixture resulting in an exothermic reactionduring which the temperature rose to 65° C. After a period thetemperature had reduced to 50° C. and the remainder of the sodiumethoxide solution and the remainder of mucobromic acid solution wereadded. The reaction temperature was maintained at 50° C. for 1 hour byexternal heating, after which the insoluble portion was removed byfiltration at that temperature, washed with ethanol and the washings andfiltrate combined. After removing the solvent by evaporation underreduced pressure the residual solid was washed with dilute hydrochloricacid (2M, 10 cm³), with water and dried to yield5-bromo-2(2-methylpro-2-yl)pyrimidine-4-carboxylic acid (3.8 g), meltingpoint 142°-144° C. (with decomposition) N.m.r and infrared spectra wereconsistent with this identification.

¹ H NMR (CDCl₃) δ: 1.45 (s, 9H); 9.05 (s, 1H); 9.44 (broad s, 1H).

Infra red (paraffin mull): 2940, 2860, 2500 (broad), 1710, 1570, 1370,1305, 1290, 1220, 1190, 1175, 750, 680 cm¹.

EXAMPLE 3

This Example illustrates the preparation of5-bromo-2-(2-methylprop-2-yl)pyrimidine.

5-Bromo-2-(2-methylprop-2-yl)pyrimidine-4-carboxylic acid (1.0 g) washeated with stirring at 145° C. after which the decarboxylated productwas obtained by distillation using a Kugelrohr apparatus under waterpump pressure. The distillate solidified on cooling to yield5-bromo-2-(2-methylprop-2-yl)pyrimidine (0.6 g) melting point 50°-51° C.N.m.r. and infra-red spectra were consistent with this identification.

¹ H nmr (CDCl₃) δ: 1.39 (s, 9H); 8.71 (s, 2H).

Infra red (paraffin mull): 2940, 2860, 1530, 1480, 1420, 1170, 1010,810, 640 cm⁻¹.

EXAMPLE 4

This Example illustrates the preparation of2-(2-methylprop-2-yl)pyrimidine-5-carboxaldehyde.

A solution of 5-bromo-2-(2-methylprop-2-yl)pyrimidine (7.6 g, 0.035M) indry tetrahydrofuran (50 cm³) was added in small portions to magnesiumturnings (0.95 g, Grignard grade) in the presence of a few crystals ofiodine. The rate of addition was controlled by the rate of theexothermic reaction. When the addition was complete the mixture waswarmed to complete the reaction. After cooling the mixture to 5° C., asolution of dimethyl formamide (2.58 g) in tetrahydrofuran (15 ml) wasadded thereto dropwise. The mixture was allowed to warm to the ambienttemperature with stirring over a period of 2 hours and kept for 16 hourswithout stirring. After adding water (5 cm³) to the mixture thetetrahydrofuran was removed by evaporation under reduced pressure andthe residue partitioned between dilute aqueous ammonium chloridesolution (100 cm³) and diethyl ether (150 cm³). The aqueous phase wasextracted with ether (150 cm³) and the extract combined with the etherphase, washed with water, and dried over anhydrous magnesium sulphate.Evaporation of the ether under reduced pressure yielded an oily solidresidue (5.8 g) which was purified by dry column chromatography using asilica column eluted with a mixture of methylene chloride (100 parts byvolume) and ethyl acetate (2 parts by volume) to give2-(2-methylprop-2-yl)pyrimidine-5-carboxaldehyde (3.4 g) melting point82°-83° C.

Infra red (paraffin mull): 2940, 2860, 1700, 1590, 1430, 1230, 1150,860, 650 cm⁻¹.

EXAMPLE 5

This Example illustrates the preparation of ethyl3-[2-(1,1-dimethylethyl)pyrimidin-5-yl]propenoate.

A solution of 0,0-diethyl ethoxycarbonylmethylphosphonate (3.93 g) indry diethyl ether (20 cm³) was added dropwise to a stirred suspension ofsodium hydride (0.54 g of a 50% oil dispersion) in dry diethyl ether (30cm³) at -5° C. and the mixture stirred thereafter for a further periodof 90 minutes. A solution of2-(2-methylprop-2-yl)pyrimidine-5carboxaldehyde (2.88 g) in dry diethylether (40 cm³) was added dropwise to this stirred mixture at 0° C., theresultant mixture allowed to warm to the ambient temperature withstirring over 2 hours after which it was kept at the ambienttemperatures for 16 hours. The mixture was partitioned between water(150 cm³) and diethyl ether (250 cm³), the aqueous phase extracted withether (250 cm³) and the extracts combined with the ethereal phase. Afterwashing with water (200 cm³) and drying over anhydrous magnesiumsulphate, the solvent was evaporated under reduced pressure and residualoil subjected to dry column chromatography using a silica column and, aseluent, dichloromethane containing 5% v/v ethyl acetate, to yield ethyl3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]propenoate (3.6 g) whichsolidified on standing, melting point 43°-45° C. N.m.r. and infra-redspectral data indicate the product as consisting of the trans isomer.

¹ H NMR (CDCl₃) δ: 1.35 (t, 3H); 1.42 (s, 9H); 4.24 (q, 2H); 6.50 (d,1H); 7.60 (d, 1H); 8.82 (s, 2H).

Infra red (paraffin mull): 2960, 1730, 1645, 1590, 1485, 1440, 1320,1185, 1155 cm⁻¹.

EXAMPLE 6

This Example illustrate the preparation of ethyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate.

A solution of n-butyllithium (10.6 cm³ of a 1.55M solution in hexane)was added slowly to a stirred solution of prop-2-yl triphenylphosphonium iodide (7.1 g) in dry tetrahydrofuran (20 cm³) at theambient temperature under a nitrogen atmosphere and the resultantmixture stirred for a further 15 minutes after which a solution of ethyltrans 3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]propenoate (3.2 g) in drytetrahydrofuran (25 cm³) was added dropwise at -5° C. After stirring fora further period of 30 minutes during which time the mixture warmed tothe ambient temperature it was kept at the ambient temperature for 16hours. The mixture was partitioned between water (300 cm³) and diethylether (200 cm³) and the aqueous phase extracted with ether (2×200 cm³)and the extracts combined with the ethereal phase. After washing withwater (2×100 cm³) and drying over anhydrous magnesium sulphate, theether was removed by evaporation under reduced pressure to yield aresidual oil which was subjected to dry column chromatography using asilica column eluted first with dichloromethane (to remove triphenylphosphine) and then with a mixture of dichloromethane (100 parts byvolume) and ethyl acetate (5 parts by volume) to yield ethyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (2.8 g), the identity of which was confirmed by infra redand n.m.r. spectroscopy.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.31 (t, 3H); 1.40 (s, 12H); 1.96 (d,1H); 2.54 (d, 1H); 4.2 (q, 2H); 8.5 (s, 2H).

Infra red (liquid film): 2960, 1730, 1485, 1450, 1420, 1260, 1180, 1165cm⁻¹.

Mass spectroscopy (M⁺): 276.

EXAMPLE 7

This Example illustrates the preparation oftrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylic acid.

A solution of ethyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (2.6 g) in ethanol (50 cm³) was mixed with a solution ofsodium hydroxide (1.0 g) in water (50 cm³) and the mixture stirred atthe ambient temperature for 5 hours. After removal of the bulk of theethanol by evaporation under reduced pressure the pH of the residualmixture was adjusted to 3 with dilute hydrochloric acid. The mixture wasextracted with diethyl ether (2×200 cm³), and the combined extractswashed with water and dried over anhydrous magnesium sulphate.Evaporation of the ether under reduced pressure yieldedtrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylic acid (2.1 g), melting point 168°-9° C.

¹ H NMR (CDCl₃) δ: 1.03 (s, 3H); 1.41 (s, 9H); 1.48 (s, 3H); 2.02 (d,1H); 2.6 (d, 1H); 8.57 (s, 2H).

Infra red (paraffin mull): 2940, 1700, 1485, 1430, 1335, 1250, 1230,1210 cm⁻¹.

Mass spectroscopy (M⁺): 248.

EXAMPLE 8

This Example illustrates the preparation of 3-phenoxybenzyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate.

A mixture oftrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylic acid (500 mg), 3-phenoxybenzylbromide (552 mg), anhydrouspotassium carbonate (304 mg) and acetone (10 cm³) was heated at thereflux temperature for 2 hours with stirring after which it was kept atthe ambient temperature for 16 hours. After removing the solidprecipitate by filtration the filtrate was concentrated by evaporationunder reduced pressure. The residual oil was subjected to highperformance liquid chromatography (Gilson) using a silica column and, aseluent, a mixture of dichloromethane (100 parts by volume) and ethylacetate (2 parts by volume). The product, 3-phenoxybenzyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)-pyrimidin-5-yl]cyclopropanecarboxylate (800 mg) was obtained as an oil and identification wasconfirmed by n.m.r. and infra red spectroscopy.

¹ H NMR (CDCl₃) δ: 0.98 (s, 3H); 1.40 (s, 12H); 2.02 (d, 1H); 2.56 (d,1H); 5.15 (s, 2H); 6.8-7.5 (m, 9H).

Infra red (liquid film: 2960, 1730, 1590, 1490, 1260, 1220, 1160 cm⁻¹.

Mass spectroscopy (M³⁰ ): 430.

EXAMPLE 9

This Example illustrates the preparation of4-allyl-2,3,5,6-tetrafluorobenzyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecaroboxylate.

Dicyclohexylcarbodiimide (420 mg) was added in portions to a stirredmixture oftrans-2,2-dimethyl-3-[2-(dimethylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate (504 mg), 4-allyl-2,3,5,6-tetrafluorobenzyl alcohol (462mg-containing a minor amount of isomeric2-allyl-3,4,5,6-tetrafluorobenzyl alcohol), 4-dimethylamino pyridine (5mg) and dry dichloromethane (10 cm³) at the ambient temperature and theresultant mixture stirred for a further period of 105 minutes afterwhich it was kept at the ambient temperature for 16 hours. The solidprecipitate was removed by filtration, washed with ether and thewashings combined with the filtrate. After removal of the solvent byevaporation under reduced pressure the residual oil was subjected toHPLC (Gilson) using a silica column and, as eluent, a mixture ofdichloromethane (100 parts by volume) and ethyl acetate (2 parts byvolume) to give a product consisting of 94% by weight of the4-allyl-2,3,5,6-tetrafluorobenzyl ester and 6% by weight of the2-allyl-3,4,5,6-tetrafluorobenzyl ester oftrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylic acid (650 mg), as an oil which solidified on standing,melting point 64°-66° C. The identification was confirmed by n.m.r.,infra red and mass spectroscopic analysis.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.39 (s, 12H); 1.96 (d, 1H); 2.56 (d,1H); 3.5 (m, 2H); 4.9-5.3 (m, 4H); 5.6-6.1 (m, 1H); 8.48 (s, 2H).

Infra red (paraffin mull): 2960, 2930, 2860, 1735, 1490, 1460, 1440,1420, 1330, 1150 cm⁻¹.

Mass spectroscopy (M⁺): 450.

EXAMPLE 10

By the use of a procedure similar to that described in Example 84-methyl-2,3,5,6-tetrafluorobenzyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate was obtained as a colourless oil from the carboxylic acidand the benzyl bromide.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.39 (s, 12H); 196 (d, 1H); 2.30 (m,3H); 2.56 (d, 1H); 5.28 (s, 2H); 8.48 (s, 2H).

Infra red (liquid film): 2960, 1740, 1495, 1420, 1290, 1155, 1075 cm⁻¹.

Mass spectroscopy (M⁺): 424.

EXAMPLE 11

By the use of a procedure similar to that described in Example 9 thefollowing esters were obtained:

(a) 6-phenoxypyrid-2-ylmethyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and 6-phenoxypyrid-2-ylmethanol.

¹ H NMR (CDCl₃) δ: 1.01 (s, 3H); 1.41 (s, 12H); 2.08 (d, 1H); 2.58 (d,1H); 5.18 (s, 2H); 6.7-7.8 (m, 8H); 8.50 (s, 2H).

Infra red (liquid film): 2960, 1730, 1600, 1580, 1490, 1540, 1250, 1160cm⁻¹.

Mass spectroscopy (M⁺): 431.

(b) 2-methyl-3-phenylbenzyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and 2-methyl-3-phenylbenzylalcohol.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.40 (s, 12H); 2.06 (d, 1H); 2.25 (s,3H); 2.60 (d, 1H); 5.27 (s, 2H); 7.1-7.5 (m, 8H); 8.50 (s, 2H).

Infra red (liquid film): 2960, 1730, 1485, 1420, 1160, 760, 705 cm⁻¹.

Mass spectroscopy (M⁺): 428.

(c) α-cyano-3-phenoxybenzyltrans-2,2-dimethyl-3-[2-(2-methyl-prop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and α-cyano-3-phenoxybenzylalcohol.

¹ H NMR (CDCl₃) δ: 0.99 (s); 1.04 (s); 1.35 (s); 1.39 (s); 1.45 (s);2.05 (m); 2.6 (m); 6.42 (s); 6.44 (s); 7.26 (m); 8.46 (s); 8.50 (s).

(Integration consistent with 2:1 mixture of diastereoisomers).

Infra red (liquid fim): 2960, 1740, 1590, 1485, 1250, 1140, 695 cm⁻¹.

Mass spectroscopy (M⁺): 455.

(d) 1-cyano-1-(6-phenoxypyrid-2-yl)methyltrans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and1-cyano-1-(6-phenoxypyrid-2-yl)methanol.

¹ H NMR (CDCl₃) δ: 1.00 (s); 1.02 (s); 1.35 (s); 1.40 (s); 2.1 (m); 2.6(m); 6.4 (3s); 6.9 (d); 7.2 (m); 7.8 (dd); 8.50 (2s).

(Integration consistent with 1:1 mixture of diastereoisomers).

Infra red (liquid film): 2960, 1745, 1595, 1490, 1450, 1260, 1140, 695cm⁻¹.

Mass spectroscopy (M⁺): 456.

(e) 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylate from the carboxylic acid and 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.40 (2s, 12H); 1.95 (d, 1H); 2.55 (d,1H); 3.40 (s, 3H); 4.50 (m, 2H); 5.30 (m, 2H); 8.50 (s, 2H).

Infra red (paraffin mull): 1735, 1595, 1490, 1295, 1150, 910, 880, 770cm⁻¹.

Mass spectroscopy (M⁺): 454.

(f) (±)-1-(6-phenoxypyrid-2-yl)ethyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and(±)-1-(6-phenoxypyrid-2-yl)ethanol.

¹ H NMR (CDCl₃) δ: 1.0 (s); 1.33 (s); 1.40 (s); 1.5 (s); 1.8 (s); 2.05(2d); 2.50 (2d); 5.85 (q); 6.7 (d); 7.2 (m); 7.65 (dd); 8.50 (2s).

(Integration consistent with 3:2 mixture of diastereoisomers).

Infra red (liquid film): 2980, 1730, 1600, 1580, 1445, 1260, 1170, 990,700 cm⁻¹.

Mass spectroscopy (MH⁺): 446.

(g) 4-fluoro-3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl)cyclopropanecarboxylate from the carboxylic acid and 4-fluoro-3-phenoxybenzylalcohol.

(h) pentafluorobenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]cyclopropanecarboxylate from the carboxylic acid and pentafluorobenzyl alcohol.

(g) (±)-α-ethynyl-3-phenoxybenzyl(±)-trans-2,2-dimethyl-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl)cyclopropanecarboxylate from the carboxylic acid and (±)-α-ethynyl-3-phenoxybenzylalcohol.

EXAMPLE 12

This example illustrates the preparation of (±)-α-cyano-3-phenoxybenzyl(±)-trans-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]-2,2-dimethylcyclopropanecarboxylate (Compound IV) and separation of its constituent pairs ofenantiomeric isomers.

A stirred mixture of(±)-trans-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]-2,2-dimethylcyclopropanecarboxylic acid (3.2 g), 3-phenoxybenzaldehyde cyanhydrin (3.8 g,contaminated with ca. 20% 3-phenoxybenzaldehyde),4-dimethylaminopyridine (100 mg) and dichloromethane (100 cm³) wastreated with portions of dicyclohexyl carbodiimide (2.8 g) at theambient temperature (ca. 24° C.). After stirring for two hours themixture was kept at the ambient temperature for 16 hours, filtered andthe collected solids washed with dichloromethane. The combined filtrateand washings were concentrated by evaporation of the solvent underreduced pressure and the residual oil purified by h.p.l.c. (Gilson)using a silica column eluted with a mixture of dichloromethane (100parts by volume) and ethyl acetate (5 parts by volume). The initialfractions yielded a mixture of the desired product with3-phenoxybenzaldehyde, the later fractions gave pure(±)-α-cyano-3-phenoxybenzyl(±)-trans-3-[2-(2-methylprop-2-yl)pyrimidin-5-yl]-2,2-dimethylcyclopropanecarboxylate (5.3 g) in the form of a gum consisting of a mixture of tworacemic pairs of enantiomeric isomers in a ratio of 2:1. The initialfractions were rechromatographed using a 2.5 cm silica column and thesame eluent at a rate of 30 cm³ /minute to give the faster running (lesspolar) pair of enantiomeric isomers (120 mg). The more polar (fasterrunning) pair of enantiomeric isomers (21 mg) was obtained by similarrechromatography of the later fractions (containing the 2:1 mixture (A)of isomer pairs). The product consisted of a 95:5 mixture of the morepolar and less polar isomers. Recombination of rejected fractions andevaporation gave a 7:1 mixture (B) of the less polar and more polarisomers.

In biological tests using adult red spider mites (Tetranychus urticae)on french bean leaves the more polar pair of enantiomeric isomers wasabout ten times more effective (LC₅₀ =4.5 ppm) than the less polar pair(LC₅₀ =49 ppm).

A mixture of the less polar and more polar pairs of enantiomeric isomersin a ratio of 7:1 (10 mg) was dissolved in isopropanol (0.1 cm³)containing triethylamine (5% by weight) was stirred at room temperature.After 22.5 hours the ratio was approximately 1:1 due to base inducedepimerisation at the α-carbon of the alcohol moiety.

    ______________________________________                                        .sup.1 H NMR (CDCl.sub.3) δ: (A)                                                         0.95 (s); 1.0 (s); 1.35 (s);                                                  1.4 (s); 1.45 (s); 2.0 (2d);                                                  2.6 (2d); 6.4 (2s); 7.2 (m); 8.45                                             (2s)                                                         (Integration consistent with 2:1 mixture of                                   diastereoisomers).                                                            (B)              1.0 (s,3H); 1.40 (s,9H); 1.45                                                 (s,3H); 2.05 (d,1H); 2.55 (d,1H);                                             6.40 (s,1H); 7.2 (m,9H); 8.40                                                 (s,2H)                                                       Infra red (liquid film): (A)                                                                   2960, 1740, 1590, 1490,                                                       1445, 1250, 1140, 695 cm.sup.-1                              (B)              2960, 1740, 1585, 1480,                                                       1445, 1245, 1140, 695 cm.sup.-1                              ______________________________________                                    

EXAMPLE 13 Preparation of methyl (±)-trans-2,2-dimethyl-3-formylcyclopropane carboxylate

A mixture of methyl 2,2-dimethyl-3-(dimethoxymethyl)cyclopropanecarboxylate (95% (±)-trans isomer: 40.0 g), glacial acetic acid (120cm³), acetone (60 cm³) and water (280 cm³) was stirred at the ambienttemperature for 5 hours, diluted with water (1500 cm³) and extractedwith diethyl ether (1000 cm³). The aqueous residue was washed with ether(2×500 cm³) and the washings and extracts washed with saturated sodiumbicarbonate solution until free of acidity. After drying the etherealsolution over anhydrous magnesium sulphate the solvent was removed byevaporation to yield a residual oil which was purified by distillationand methyl (±)-trans-2,2-dimethyl-3-formylcyclopropane carboxylate (28.5g) collected as the fraction boiling at 46°-48° C./0.05 mm Hg.

EXAMPLE 14

Preparation of (±)-trans methyl3-[(E,Z)-2-methoxyvinyl]-2-dimethylcyclopropane carboxylate.

Sodium hydride (obtained by washing a 50% oil dispersion (9.6 g) withn-hexane to remove the oil) was suspended in dry dimethylsulphoxide (150cm³, freshly distilled from calcium hydride) and the suspension stirredunder a dry nitrogen atmosphere at 38°-40° C. for 5 hours. A solution ofmethoxymethyl triphenyl phosphonium chloride (68.8 g) in drydimethylsulphoxide (200 cm³) was added over 15 minutes whilst thereaction temperature was maintained at ca. 20° C. by external cooling.The solution of the ylid thus produced was added dropwise to a stirredsolution of methyl (±)-trans-2,2-dimethyl-3-formylcyclopropanecarboxylate (28.5 g, freshly distilled) in dimethylsulphoxide (50 cm³)whilst keeping the reaction temperature at ca. 20° C. over a period of 2hours. The mixture was stirred for a further 30 minutes and then kept atthe ambient temperature for 72 hours. Water (1500 cm³) was added, andthe mixture extracted with diethyl ether (1×1000 cm³), (2×500 cm³). Theextracts were combined, washed with water (3×300 cm³) and dried overanhydrous magnesium sulphate. The solvent was removed by evaporationunder reduced pressure and the residue triturated with petroleum ether(boiling range 60°-80° C., 150 cm³). The undissolved solid was removedby filtration and the filtrate evaporated to give a yellow oil (29.0 g)which was distilled under reduced pressure using a Kugelrohr apparatusto yield methyl(±)-trans-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropane carboxylate(21.4 g), boiling point 64° C./0.05 mm Hg.

¹ H NMR (CDCl₃) δ: 1.13 (s); 1.24 (s); 1.26 (s); 1.4 (m); 1.9 (m); 2.3(m); 3.5 (s); 3.6 (s); 3.66 (s); 4.1 (2d); 4.56 (2d); 6.0 (dd); 6.4 (d).

(Integration consistent with 2:1 mixture of (E) and (Z) isomers).

Infra red (liquid film): 2960, 1730, 1650, 1440, 1270, 1235, 1170, 920cm⁻¹.

EXAMPLE 15

This example illustrates the preparation of a mixture of methyl(±)-trans-3-[(E,Z)-2-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate and methyl(±)-trans-3-[(E,Z)-formyl-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate.

A solution of phosphoryl chloride (12.0 cm³) in 1,2-dichloroethane (10.0cm³) was added dropwise to a stirred mixture of dimethylformamide (29.5cm³) and 1,2-dichloroethane (100 cm³) at the ambient temperature. Whenthe addition was complete the mixture was stirred for a further 15minutes and cooled to 15° C. To this mixture was added portionwise asolution of methyl(±)-trans-3-[(E,Z)-2-methoxyvinyl]-2,2-dimethylcyclopropane carboxylate(10.0 g) in 1,2-dichloroethane (80 cm³). The mixture was kept at theambient temperature for 16 hours and solid anhydrous potassium carbonate(150 g) and ice added. When the exothermic reaction had subsided themixture was extracted with methylene chloride (2×300 cm³) and extractscombined and washed with water (300 cm³). After drying over anhydrousmagnesium sulphate the solvent was removed by evaporation under reducedpressure and the residual oil heated at 55° C. and 0.05 mm Hg in aKugelrohr apparatus to remove the volatile components to yield a mixturecontaining a minor amount of methyl(±)-trans-3-[(E,Z)-1-formyl-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate and a major amount of methyl(±)-trans-3-[(E,Z)-1-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate (A), (10.3 g).

¹ H NMR (CDCl₃) δ: (A) 1.0 (s); 1.05 (s); 1.27 (s); 1.30 (s); 2.0 (m);3.18 (s); 3.37 (s); 3.68 (s); 3.70 (s); 6.75 (broad s); 8.35 (broad s);8.8 (s).

(Integration consistent with 2:1 mixture of (E) and (Z) isomers).

Infra red (paraffin mull): 2960, 2720, 1730, 1600, 1450, 1410, 1280,1230, 1175 cm⁻¹.

EXAMPLE 16

This Example illustrates the preparation ofmethyl-(±)-trans-3-(2-cyclohexylpyrimidin-5-yl)cyclopropane carboxylate.

Sodium methoxide (3.2 cm³ of a 2M solution in methanol) was addeddropwise to a stirred mixture of methyl(±)-trans-3-[(E,Z)-2-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate (1.0 g; in the form of the product of Example 15 containinga minor proportion of methyl(±)-trans-3-[E,Z-1-formyl-2-methoxyvinyl]-2,2-dimethylcyclopropanecarboxylate), cyclohexanoyl amidine (1.08 g) and methanol (8 cm³) at theambient temperature and the resultant mixture heated at the refluxtemperature for 3.5 hours. The mixture was cooled to the ambienttemperature and poured into water (200 cm³) and extracted with diethylether (2×200 cm³). After washing the combined extracts with water (50cm³) and drying over anhydrous magnesium sulphate, the solvent wasremoved by evaporation under reduced pressure the residual oil waspurified by column chromatography using silica column eluted with amixture of methylene chloride (3 parts by volume) an diethyl ether (1part by volume) to yield methyl(±)-trans-3-[(E,Z)-2-dimethylamino-1-formylvinyl]-2,2-dimethylcyclopropanecarboxylate (790 mg).

¹ H NMR CDCl₃) δ: 1.0 (s, 3H); 1.4 (s, 3H); 1.2-1.8 (b, 10H); 1.95 (d,1H); 2.5 (d, 1H); 2.8 (b, 1H); 3.7 (s, 3H); 8.5 (s, 2H).

Infra red (liquid film): 2940, 2860, 1730, 1600, 1500, 1440, 1290, 1175cm⁻¹.

EXAMPLE 17

The product of Example 16 (790 mg) was converted to(±)-trans-3-(2-cyclohexylpyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylic acid (750 mg, m.p. 128°-130° C.) by the use of a proceduresimilar to that described in Example 7 except that methanol was used inplace of ethanol.

Infra red (paraffin mull): 3500-2200 (broad), 1710, 1550, 1340, 1290,1190, 1120 cm⁻¹.

Mass spectroscopy (M⁺): 274.

EXAMPLE 18

This Example illustrates the preparation of(RS)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl (1RS,trans)-3-(2-cyclohexylpyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylate.

Dicyclohexylcarbodimide (118 mg) was added to a stirred mixture of(±)-trans-3-(2-cyclohexylpyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylate (150 mg), 1-cyano-1-(6-phenoxypyrid-2-yl)methanol (130 mg),4-dimethylaminopyridine (5 mg) and dichloromethane (5 cm³) and themixture stirred at the ambient temperature for 7 hours, and kept for afurther 16 hours without stirring. The product was isolated by filteringthrough a silica column, eluting first with dichloromethane and thenwith a mixture of dichloromethane (20 parts by volume) and ethyl acetate(1 part by volume) to yield (RS)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(1RS, trans)-3-(2-cyclohexylpyrimidine-5-yl)-2,2-dimethylcyclopropanecarboxylate, (248 mg) identified by n.m.r. as a 1:1 mixture of the twopairs of enantiomeric diastereomers.

¹ H NMR (CDCl₃) δ: 1.0 (2s); 1.35 (s); 1.43 (s); 1.2-2.0 (bm); 2.05 (m);2.6 (m); 2.85 (m); 6.35 (bs); 6.9 (d); 7.25 (m); 7.8 (dd); 8.45 (2s).

(Integration consistent with 1:1 mixture of diastereomers).

Infra red (liquid film): 2940, 2860, 1745, 1600, 1450, 1150, 810, 700cm⁻¹.

EXAMPLE 19

By the use of procedures similar to that described in Example 16, thefollowing compounds were also prepared from the relevant amidines.

(i) Methyl(±)-trans-3-(2-prop-2-ylpyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylate.

¹ H NMR (CDCl₃) δ: 0.98 (s, 3H); 1.30 (s, 3H; 1.38 (s, 3H); 1.40 (s,3H); 1.95 (d, 1H); 2.25 (d, 1H); 3.2 (M, 1H); 3.75 (s, 1H); 8.48 (s,2H).

Infra red (liquid film): 2980, 1735, 1595, 1550, 1440, 1340, 1260, 1175,830 cm⁻¹.

(ii) Methyl(±)-trans-3-(2-cyclopropylpyrimidin-5-yl)-2,2-dimethylcyclopropanecarboxylate.

¹ H NMR (CDCl₃) δ: 0.96 (s, 3H); 1.05 (m, 4H); 1.40 (s, 3H); 1.95 (d,1H); 2.2 (m, 1H); 2.5 (d, 2H); 3.75 (s, 3H); 8.4 (s, 2H).

Infra red (liquid film): 3010, 2960, 1730, 1600, 1550, 1470, 1445, 1175,915 cm⁻¹.

EXAMPLE 20

By the use of procedures similar to that described in Examples 17 and 18the following insecticidal and acaricidal compound of formula I wereobtained.

(i) 2-methyl-3-phenylbenzyl(±)-trans-2,2-dimethyl-3-(2-prop-2-ylpyrimidin-5-yl)cyclopropanecarboxylate.

¹ H NMR (CDCl₃) δ: 0.99 (s, 3H); 1.30 (s, 3H); 1.38 (s, 3H); 1.42 (s,3H); 2.1 (d, 1H); 2.25 (s, 3H); 2.65 (d, 1H); 3.2 (m, 1H); 5.27 (s, 2H);7.3 (m, 8H); 8.49 (s, 2H).

Infra red (liquid film): 2980, 1730, 1595, 1550, 1425, 1240, 1165, 740,710 cm⁻¹.

(ii) (±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(±)-trans-2,2-dimethyl-3-(2-prop-2-ylpyrimidin-5-yl)cyclopropanecarboxylate.

¹ H NMR (CDCl₃) δ: 1.00 (s); 1.03 (s); 1.31 (s); 1.36 (s); 1.38 (s);1.42 (s); 2.05 (m); 2.60 (m); 3.2 (m); 6.35 (bs); 6.9 (d); 7.3 (m); 7.8(dd); 8.5 (2s).

(Integration consistent with 1:1 mixture of diastereisomers).

Infra red (liquid film): 2980, 1745, 1595, 1580, 1450, 1280, 1150, 745,700 cm⁻¹.

(iii) (±)-1-cyano-1-(6-phenoxypyrid-2-yl)methyl(±)-trans-2,2-dimethyl-3-(2-cyclopropylpyrimidin-5-yl)cyclopropanecarboxylate.

¹ H NMR (CDCl₃) δ: 1.0 (s); 1.03 (m); 1.06 (s); 1.34 (s); 1.42 (s); 2.0(2d); 2.2 (m); 28 (m); 6.4 (s); 6.9 (d); 7.3 (m); 7.8 (dd); 8.35 (2s).

(Integration consistent with 1:1 mixture of diastereoisomers).

Infra red (liquid film): 3010, 2940, 1750, 1600, 1450, 1260, 1150, 910,800, 700 cm⁻¹.

EXAMPLE 21

The insecticidal activity of Compounds I to VII is set out in thefollowing Table as a grading of A, B or C where A indicates that 80-100%mortality was observed, B indicates that 50-795 mortality was observedand C indicates that 0-49% mortality was observed. The tests wereconducted by supporting the test species on a medium (eg. leaves of asuitable food plant, or filter paper) and spraying the pests and medium(contact test--"CT" in the Table) or by spraying the medium beforeplacing the pests thereon (residual test--"RT" in the Table). Assessmentof mortality was made 72 hours after spraying except for houseflies(Musca domestica) where the assessment was made after 24 hours. In thetest the compounds were used in the form of aqueous compositioncomprising 500 parts per million of the compound prepared by dissolvingthe compound in mixture of solvents consisting of 4 parts by volume byacetone and 1 part by volume of diacetone alcohol and diluting thesolution with water containing 0.01% by weight of a wetting agent8"Lissapol" NX--"Lissapol" is a Registered Trade Mark).

                                      TABLE I                                     __________________________________________________________________________                              TYPE OF                                                                             COMPOUND                                      TEST SPECIES                                                                            STAGE                                                                              SUPPORT MEDIUM                                                                           TEST  I II                                                                              III                                                                             IV V  VI VII                                                                              VIII                        __________________________________________________________________________    Tetranychus                                                                             adults                                                                             French bean                                                                              CT    A A A A  A  A  A  A                           urticae (red   leaves                                                         spider mites)                                                                 Tetranychus                                                                             eggs French bean                                                                              CT    A A C A  A  A  A  A                           urticae (red   leaves                                                         spider mites)                                                                 Myzus persicae                                                                          mixed                                                                              Broad bean CT    A A A B  A  A  A  A                           (peach aphids) leaves                                                         Chilo partellus                                                                         larvae                                                                             Oil seed   RT    A A A A  A  A  A  A                           (maize stem    rape leaves                                                    borers)                                                                       Heliothis larvae                                                                             Cotton     RT    A C C A  A  A  A  A                           virescens (tobacco                                                                           leaves                                                         budworms)                                                                     Diabrotica                                                                              larvae                                                                             Filter paper/                                                                            RT    C A A A  A  A  C  A                           balteata       maize seed                                                     (rootworms)                                                                   Musca domestica                                                                         adults                                                                             Cotton wool/                                                                             CT    C A A B  C  B  C  C                           (houseflies)   sucrose                                                        Blatella germanica                                                                      adults                                                                             Filter paper                                                                             RT    A C C A  C  A  C  C                           (cockroaches)                                                                 __________________________________________________________________________                              TYPE OF                                                                             COMPOUND                                      TEST SPECIES                                                                            STAGE                                                                              SUPPORT MEDIUM                                                                           TEST  IX                                                                              X XI                                                                              XII                                                                              XIII                                                                             XIV                                                                              XV XVI                         __________________________________________________________________________    Tetranychus                                                                             adults                                                                             French bean                                                                              CT    B A C A  A  A  A  A                           urticae (red   leaves                                                         spider mites)                                                                 Tetranychus                                                                             eggs French bean                                                                              CT    A C A A  C  A  C  C                           urticae (red   leaves                                                         spider mites)                                                                 Myzus persicae                                                                          mixed                                                                              Broad bean CT    C C C A  A  A  A  B                           (peach aphids) leaves                                                         Chilo partellus                                                                         larvae                                                                             Oil seed   RT    A C A A  A  A  A  A                           (maize stem    rape leaves                                                    borers)                                                                       Heliothis larvae                                                                             Cotton     RT    C C C A  A  A  C  A                           virescens (tobacco                                                                           leaves                                                         budworms)                                                                     Diabrotica                                                                              larvae                                                                             Filter paper/                                                                            RT    C A C C  A  C  C  C                           balteata       maize seed                                                     (rootworms)                                                                   Musca domestica                                                                         adults                                                                             Cotton wool/                                                                             CT    A C B -- -- -- -- C                           (houseflies)   sucrose                                                        Blatella germanica                                                                      adults                                                                             Filter paper                                                                             RT    C C C C  A  C  C  C                           (cockroaches)                                                                 __________________________________________________________________________

In the Table it can be seen that the compounds exhibit usefulinsecticidal and acaricidal activity against a number of test speciesrepresenting a wide variety of insect and acarine pests of economicimportance.

We claim:
 1. A compound of formula: ##STR16## wherein Z is formyl or agroup of formula ##STR17## wherein R⁹ is an alkyl group of up to 6carbon atoms, and R² is cyclopropyl, cyclohexyl, or an α-branched alkylgroup of from 3 to 6 carbon atoms.
 2. A compound according to claim 1wherein Z is formyl and R² is selected from the group consisting ofprop-2-yl, but-2-yl, pent-2-yl, pent-3-yl, 2-methylprop-2-yl,2-methylbut-2-yl, cyclopropyl, and cyclohexyl.